1. Technical Field
The present disclosure relates to a switching circuit. More particularly, the present disclosure relates to a switching circuit adapted in an LED circuit.
2. Description of Related Art
LEDs are estimated to be four times as efficient as conventional incandescent lights. They are also claimed to be more economically sound than compact fluorescent bulbs that contain harmful mercury and are supposed to last a lot longer than the conventional lighting. Thus, LEDs may become the mainstream of the lighting technology.
The switching circuit in the LED circuit performs charging and discharging activities on the LEDs. The conventional design of the LED circuit has a load connected to the output of the LEDs. In order not to have too much power dissipation on the load, a feedback mechanism is used to connect the output with a comparator to lock the output voltage of the LEDs at a pre-determined value, which is a small value, to lower the power dissipation. In order to match the pre-determined value, the comparator is used to compare the output voltage to a reference voltage, wherein the reference voltage is set to be the pre-determined value. Therefore, the reference voltage needs to be precise. A measuring process of the reference voltage is performed to make sure that the reference voltage doesn't deviate from the pre-determined value too much. However, an error is easily generated during the measuring process because the output voltage is too small and is easy to be affected by the measuring device, such as a probe. Therefore, it's hard to check the precision of the reference voltage.
Accordingly, what is needed is a switching circuit adapted in an LED circuit with a precision-checking mechanism to provide a compensation mechanism without losing of the linearity.